Previous studies by Oregon Health & Science University researchers have shown that taking vitamin C during pregnancy may help reduce some of the damage to infant health caused by smoking. A new study from the research team demonstrates how: Vitamin C helps offset decreased placental blood flow found in pregnant mothers who smoke.
In their newest study published in Scientific Reports, the team tested whether vitamin C could improve the health of the placenta and help protect the fetus from the harmful effects of smoking.
Smoking during pregnancy can harm the development of a baby's lungs and other organs, including the brain, kidneys and blood vessels. This is because nicotine from the mother's cigarette smoke crosses the placenta and directly affects the growing fetus. As a result, children born to mothers who smoke during pregnancy often have trouble with lung function later in life.
In the clinical research trial, researchers randomized two cohorts of women who were unable to quit smoking during pregnancy. They all received a standard prenatal vitamin with 60 mg of vitamin C, but one group also received an additional 500 mg of vitamin C.
The study was led by Eliot Spindel, M.D., Ph.D., professor of neuroscience in the the Oregon National Primate Research Center at OHSU, and Cindy McEvoy, M.D., professor of pediatrics in the OHSU School of Medicine, as part of their work with their National Institutes of Health funding from the National Heart, Lung and Blood Institute, its Office of Dietary Supplements, and the Environmental Influences on Child Health Outcomes program.
The team used a method called Doppler ultrasound to measure blood flow in the umbilical cord and found that vitamin C helped improve blood flow in pregnant smokers, bringing it closer to the levels seen in nonsmokers.
"It is clear that placental development is abnormal in women who smoke," said Spindel, who is corresponding author on the newest study. "We had data from our studies with nonhuman primates suggesting that vitamin C could offset some of those negative effects, which then led us to study this in humans. In this human clinical trial, it is important to note that some, but not all, abnormalities were prevented by vitamin C intake."
The researchers found that vitamin C helped offset decreased placental blood flow found in pregnant mothers who smoke. By studying the placenta directly after birth, they also foud that vitamin C may help improve the development of blood vessels and overall placental function in babies of smokers.
Despite strong efforts to encourage quitting smoking, the researchers said more than half of women who smoke continue to do so during pregnancy, and this increases the risk of problems for both the mother and baby. Studies in animals, including nonhuman primates, have shown that nicotine directly affects the baby's lung development, which is why protecting the baby from nicotine is so important. Because nicotine appears to be an important part of why tobacco affects fetal development, vaping and other nicotine products used during pregnancy are also likely to affect lung development.
"Nicotine is highly addictive, and there are a lot of reasons, including genetic disposition, that make it harder for some people to quit," McEvoy said.
"We've been able to demonstrate in our other studies that the offspring of the women who received the vitamin C had significantly improved pulmonary function tests at ages 3 months and 12 months," she added. "We were able to continue to follow these children through age 5, and they still had improved lung function."
The researchers point out that while vitamin C intake may lead to better respiratory outcomes, smoking during pregnancy is also linked to other negative effects of smoking for the baby, such as premature birth, reduced brain development and less overall growth, which t vitamin C may not help.
In addition to Spindel and McEvoy, the multidisciplinary OHSU research team included Lyndsey Shorey-Kendrick, Ph.D., Kristin Milner, B.A., Brittany Vuylsteke, M.P.H., Terry Morgan, M.D., Ph.D., Victoria H. J. Roberts, Ph.D., Jamie Lo, M.D., M.C.R., Antonio Frias, M.D., Byung Park, Ph.D., Lina Gao, Ph.D., Annette Vu, B.A., Shannon M. O'Sullivan and Cynthia D. Morris, Ph.D., M.P.H., plus David M. Haas, M.D. and Robert S. Tepper, M.D., Ph.D., from Indiana University.
Supported by the National Heart, Lung and Blood Institute (R01 HL105447 and R01 HL 105460) with co-funding from the Office of Dietary Supplements (ODS) and by P51 OD0110925 and National Institutes of Health grant UH3 OD023288 from the Environmental influences on Child Health Outcomes Program. Additional support from the Oregon Clinical Translational Research Institute (OCTR) funded by the National Center for Advancing Translational Sciences (UL1TR000128). The content is solely the responsibility of the authors and does not necessarily represent the official views of any funders.
All research involving animal subjects at OHSU must be reviewed and approved by the university's Institutional Animal Care and Use Committee (IACUC). The IACUC's priority is to ensure the health and safety of animal research subjects. The IACUC also reviews procedures to ensure the health and safety of the people who work with the animals. The IACUC conducts a rigorous review of all animal research proposals to ensure they demonstrate scientific value and justify the use of live animals.
